Inkjet printing devices generally provide high-quality image printing solutions at reasonable cost. Inkjet printing devices print images by ejecting ink drops through a plurality of nozzles onto a print medium, such as a sheet of paper. Nozzles are typically arranged in one or more arrays, such that properly sequenced ejection of ink from the nozzles causes characters or other images to be printed on the print medium as the printhead and the print medium move relative to each other. In a specific example, a thermal inkjet (TIJ) printhead ejects drops from a nozzle by passing electrical current through a heating element to generate heat and vaporize a small portion of the fluid within a firing chamber. In another example, a piezoelectric inkjet (PIJ) printhead uses a piezoelectric material actuator to generate pressure pulses that force ink drops out of a nozzle.
Improving the image print quality from inkjet printing devices typically involves addressing one or more of several technical challenges that can reduce image print quality. For example, pigment settling, air accumulation, temperature variation and particle accumulation within printhead modules can contribute to reduced print quality and eventual printhead module failure. One method of addressing these challenges has been to recirculate ink within the ink delivery system and print modules. However, the cost and size of macro-recirculation systems designed for this purpose are typically only appropriate for high-end industrial printing systems. In addition, product architectures that attempt to address the cost issue with less complexity typically become associated with poor performance and reliability.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.